1. Technical Field of the Invention
The present invention refers to the control of the temperature of the brain of a living being, and especially to cooling of the brain.
In pathological conditions, the body temperature or the temperature of the body parts of a living being influences the healing process and the risk of permanent damage. Cancer cells, for example, are heat sensitive and a local heating of the blood flow around a cancer tumor may for some types of cancer constitute a treatment resulting in restrained tumor growth or in some cases even in a shrinking of the tumor. In other cases cooling of a body part may be important to reduce adverse secondary symptoms of the pathological condition.
In the case of a stroke, the blood flow to the brain is reduced (ischemia) due to a hemorrhage or the clogging of a blood vessel. This condition will cause permanent functional deficits unless treatment to restore blood flow and protect nerve cells is initiated at an early stage, which will reduce the loss of bodily functions, such as paralysis. It is well known that cooling the brain effectively blocks the development of cellular damage after an episode of ischemia. Cooling of the patient suffering transient circulatory arrest to the brain results in a reduction of the symptoms of neurological deficit. However, there are certain problems associated with whole body cooling. One is that the cooling is not fast enough to effectively use its protective potential. Another problem is that whole body cooling must be carried out under close control of physiological parameters or under anesthesia. Yet another problem is that there is a risk of cardiovascular complications.
In the case of a circulatory arrest, the brain can suffer permanent damage if the arrest exceeds a time period of about 5–15 minutes. However, if the temperature of the brain is lowered before or after the arrest the brain damage is diminished.
In the case of brain trauma the brain suffers from open or close head concussion. Hypothermia has been shown to diminish traumatic brain injury in such cases.
There are several methods in the prior art to carry out a more isolated cooling of a single organ or body part. An example of cooling of the brain in a human being is disclosed in the patent document WO 98/23217, relating to a method of cerebral retro-perfusion and retro-infusion, involving the cooling of arterial blood that then is returned to the entire brain. However, this method entails a large and complicated surgical procedure, which delays the inset of an actual treatment.
The U.S. Pat. No. 5,906,588 discloses a method and a device for heart-lung bypass and cooling of a specific body part. This disclosure primarily relates to complicated heart surgery and organ transplantation.
The U.S. patent application Ser. No. 10/072,857 discloses a first phase comprising the step of introducing an infusion catheter for infusion of a temperature controlled infusion solution or perfusate into a vein initiating quick general body hypothermia. An optional second phase, wherein a second infusion catheter is introduced into an artery of the living being, the second infusion catheter being configured to provide selective temperature control of the brain and infusion of other important substrates and pharmacological compounds into the brain. A third phase is also disclosed, wherein an extra-corporeal circuit is established between a vein and an artery. Blood is withdrawn from the vein, the temperature of the blood is modified outside the body and the blood is returned to the body through the artery.
2. Purpose of the Invention
A purpose of the present invention is to provide a system and a method for quick and efficient control of the temperature of the brain without changing the temperature of the rest of the body. An aim of the invention is to provide a system and a method that is simple and initially does not require specialized personnel acquainted with for example radiology or other diagnostic imaging techniques.